A 1ST-PRINCIPLES THEORY FOR MAGNETIC CORRELATIONS AND ATOMIC SHORT-RANGE ORDER IN PARAMAGNETIC ALLOYS .1.

A formalism is derived for describing both magnetic correlations and atomic short-range order (ASRO) in the paramagnetic state of a magnetic alloy. It is based on a 'first-principles', finite-temperature, electronic density-functional, mean-field grand potential of the random alloy in which the thermally induced spin fluctuations are modelled in terms of 'local moments'. For proper comparison, calculations based on this work should be tested against data from experiments on samples at 'high temperature' (either in situ or rapidly quenched). The calculated ASRO Can be compared to any atomic diffuse-scattering data, whereas the calculated magnetic correlations must be compared to polarized-neutron diffuse-scattering data